Answer:
25
Step-by-step explanation:
Hello, please consider the following.
[tex]\text{Let's note the 7 digits } x_i \text{ for }i = 0,1,2,3,4,5,6\\\\\text{We can write 7 equations as below.}\\\\(1) \ x_0+x_1+x_2+x_3=16\\\\(2) \ x_1+x_2+x_3+x_4=16\\\\(3) \ x_2+x_3+x_4+x_5=16\\\\(4) \ x_3+x_4+x_5+x_6=16\\\\(5) \ x_0+x_1+x_2+x_3+x_4=19\\\\(6) \ x_1+x_2+x_3+x_4+x_5=19\\\\(7) \ x_2+x_3+x_4+x_5+x_6=19[/tex]
This is the translation in mathematical equations.
(5)-(1) gives [tex]x_4=19-16=3[/tex]
(6)-(2) gives [tex]x_5=19-16=3[/tex]
(7)-(3) gives [tex]x_6=19-16=3[/tex]
So, by using (1)
[tex]x_0+x_1+x_2+x_3+x_4+x_5+x_6=(x_0+x_1+x_2+x_3)+3+3+3=16+9=25[/tex]
Thank you
PS: If we go a little bit further it is not so hard to find that the number actually is 3337333
